Urban theorist and former mayor of Bogota Enrique Penalosa, makes this important point about the political significance of dedicating lanes to his city's buses:
[TransMilenio system] is a powerful symbol of democracy... It shows that public transportation has a priority in the use of road space over private cars.
Not only that, but dedicating lanes to buses is actually not expensive. Begin at 1:33:
If our city took the democracy of public transportation at all seriously, this is what RapidRide would look like...